Based on the photos associated with dog #45 and the description given in the blog, I believe the 10th series is back at Goose Pond where the third series was held. I looked at the following WEB site which shows a satellite view of the pond. In the satellite view, North is approximately at 12 noon and South at 6.
If this WEB site does not work for you, perhaps you can find another site that shows Goose Pond.
I believe the long point associated with the 2nd bird down – Left Retired (LR), is the point under the “Goose Pond” label. Based on the descriptions for the four marks and the photos on the blog this would put the mat in the general area of the very small triangle formed by the roads in the middle of the view.
Probably makes little difference now, but you were pretty darn close, George. The line was a little farther back and up the hill a bit. Just down from the 4th clump of bushes from the dam.